Genzyme Corp has met the first in a series of deadlines imposed by U.S. regulators for fixing problems at its Boston plant, a milestone that could bolster the biotech company's argument that it is worth more than the $18.5 billion being offered by French drugmaker Sanofi-Aventis.

Genzyme had been given until Nov. 28 to move certain vial-filling and finishing operations out of the plant, which was temporarily closed last year due to a viral contamination.

On Wednesday, Genzyme said it had met that deadline, imposed under a government consent decree, and had moved the vial-filling and finishing of products sold in the United States to its plant in Waterford, Ireland, and to a contract manufacturer.

A consent decree places one or more of an offending company's manufacturing facilities under third-party control. Genzyme's multiyear remediation plan is being overseen by Quantic Group, a consultancy that will monitor the company and submit reports to regulators for five years after the remediation is complete.

The temporary closure of the company's Allston Landing plant in Boston led to shortages of Cerezyme, its drug to treat Gaucher disease, and Fabrazyme, a drug to treat Fabry disease. The closure sent the company's sales and stock price plummeting.

In November 2009, Genzyme announced that stainless steel fragments, rubber and fiber-like materials had been found in some of its drugs due to aging machinery in the fill-finish area, prompting regulators to require that the company move those operations out of the plant.

The Cambridge, Mass.-based company said all fill-finish activities for Cerezyme, Fabrazyme, its Pompe disease drug Myozyme, and Thyrogen, a drug to help diagnose thyroid cancer, that are sold in the United States, have now been moved out of the facility. It said previous restrictions on the marketing and distribution of Thyrogen within the United States have been lifted.

The Nov. 28 deadline is the first of a number of deadlines the company must meet in order to satisfy the terms of the consent decree. It must move the fill-finish operations for products sold outside the United States by Aug. 31, 2011.

If Genzyme fails to meet its deadlines, the company, which has already been forced to disgorge $175 million in profits from past sales of drugs made at the Boston plant, could be required to pay $15,000 a day per affected drug until it is back in compliance.

Pressure on Genzyme to meet its deadlines is all the more intense because any misstep could cause its stock to fall and make Sanofi's offer of $69 a share more palatable to investors, who have until Dec. 10 to tender their shares.

Genzyme is demanding Sanofi raise its offer before it will sit down and negotiate, saying Sanofi's bid is "opportunistic" and not a reasonable starting point for discussions.

The company points to the measures it has taken to address its problems. It has reorganized management, installed new heads of quality control and compliance, increased the transparency of its compensation practices, and brought its accounting in line with its peers.

In October, the company said it expects 2011 revenue of $5 billion to $5.1 billion, rising to as much as $7.5 billion by 2013.

It projected 2011 earnings of $4.30 to $4.60 a share.

When Sanofi announced its takeover offer in August, the bid was about 19 times analysts' average forecast for Genzyme's 2011 earnings. Genzyme argues that analysts' expectations were outdated.

Applying a multiple of 19 to Genzyme's October forecast would imply a value of $89 a share. Analysts and investors polled by Reuters expect a deal to be sealed closer to $78 a share.

Genzyme argues that Sanofi is not placing enough value on its experimental multiple sclerosis drug Campath. Sanofi estimates the drug could generate annual sales of about $700 million, while Genzyme sets the figure at $3.5 billion.

Genzyme will be holding an investor day in December to make its case for why it considers Campath so valuable. The exact date has yet not been set.